fuse # 7 burned every day on 2011 Mercedes-Benz C300

I don't find anything on the owner manual about that fuse,no information at all,even is not mentioned on the fuse diagram,every day I got the same problem,I bougth this car salvage,but it was wit very little damage on the front end,somebody can help me?dont know where can I find more info about this fuse,thanks